Linux as an ISDN Based Remote Access Server?

Richard Becke asks: " I am planning to set up a Linux box as an ISDN-based dialin server for my company network. I have not been able to find any information about using multiple ISDN cards with Linux. We need to serve at least 6 simultaneous connections. Any ideas or tips would be most welcome. The question can be rephrased like this: How do i set up a Linux-based ISP solution?"

One other thing ...

[Anonymous Coward]

If you can get a PRI in, you can (well, you can with SBT) get just some of the channels activated. With a Spellcaster PRI card you can use just those channels. I have several friends doing that now (there used to be a much larger difference between a PRI and fractional T1 in Texas). One nice thing is that you can get the ISA PRI card so that you don't have to waste a PCI slot.

go ahead!

[Anonymous Coward]

isdn dial-in is among the most stable services at the ISP where i work. (we could almost count the total downtime in seconds for the last two years!)

we use passive cards with the HiSax driver, but the eicon server cards (active cards) looks very promising (i think this is http://www.eicon.de) with an active card you could be able to accept modem v.34 and v.90 calls as well...

read /usr/src/linux/Documentation/isdn/* from a recent kernel tree, there is a lot of useful info there. if you like linux, you may want to avoid teles cards (their intellectual property policies suck)

disclaimer: i made my experiences in europe, the isdn signalling protocol is different in the US, and i do not know how well it is implemented or how stable isdn service from the telco is...

again: just do it ;)

I'm looking at doing this same kind of thing

[Evan]

What are the best places to find information about this sort of thing? In another few weeks, I would really like to set up a dial-in/firewall box to allow 4 different locations to share a WAN through ISDN connections, with occasional regular modem dial-in if I can manage it.

I don't expect any problems setting up the firewall part, but the ISDN part is really bothering me. I've considered using a pair of routers (Netgear, Ascend, etc), a pair of ISDN "modem"s (Impact IQ), or an internal card (Spellcaster). I've had extensive problems with cheap unattended routers in the past, and trying to run 256Kbps through serial ports bothers me. On the other hand, I can't find *anyone* who sell the frigging cards. Lots of *manufacturers*, yes, but no pricing or sales info unless I call (and that only worked for Spellcaster, nobody else has called back). Plus, the cards appear to be twice as expensive as the routers and "modem"s, which makes no sense to me.

This would make a great HOWTO, I think. If I manage it, I'll write one.

Open Source solution

[TestGeek]

I admit to being biased ....... Ariel Corp makes plugin cards designed for Remote Access, and support ISDN and V.90 connections. Look at the Ariel HomePage [ariel.com] for details. The drivers for these cards were recently open sourced, and they are available with the RedHat 6.x distros.

Re:I'm looking at doing this same kind of thing

[WowMan]

Go syncronous. The cards are expensive ($400) but it is the fastest solution. With this setup, you can use a syncronous ISDN terminal adapter, which are usually much higher in quality. I like Adtran myself

Some pointers

[mconstable]

I've been selling ISDN based ISP servers in Australia for nearly two years now with a moderate degree of success. Fortunately the main internal components, the internal ISDN card and the 8-port analog modem cards, are made locally.

http://www.netserva.com [netserva.com] for some indication of the hardware and I understand the company in Melboune who supply the ISDN card (passive HiSax based) also now have a US port of the isdn4linux code and have a sales outlet or partner in the US.

http://www.traverse.com.au [traverse.com.au] may be able to help you directly with some info.

http://www.moreton.com.au [moreton.com.au] are the people that provide the 8-port PCI 56k V90 modem card which I also believe is usable in the US.

These pointers may help you evaluate some possibilities.

--markc

Re:DONT USE SERIAL PORT DEVICES

[matts.nu]

I am using a serial port device, the USRobotics (aka 3Com) Courier I-Modem. There is nothing slow about this device. I have 30 ms ping and 64kb throughput to the corporate net I dial into. Though I admit that I haven't tried 128kb, mainly because the serial port in my computer don't support more than 115kb (the I-Modem will do 230kb).